Quickly extendable mechanical jack



Dec. 19, 1961 N. F. ATHERTON EI'AL 3,013,772

QUICKLY EXTENDABLE MECHANICAL JACK Filed Sept. 22, 1958 6 IN VEN TORSN94 F HTHEZTON Pan/04o Mxi'esjoav A T' TOEIVE'VS United States Patent3,013,772 QUICKLY EXTENDABLE MECHANICAL JACK Neii F. Atherton, Bayside,and Donald W. Sessody, Milwaukee, Wis., assignors to Applied PowerIndustries, Inc., a corporation of Wisconsin Filed Sept. 22, 1958, Ser.No. 762,546 3 Claims. (Cl. 254-99) The present invention relates tomechanical lifting jacks.

Devices of this nature usually employ a threaded rod which is rotated tocause a load-engaging saddle or the like to be moved relative to therest of the jack. This type of screw adjustment is desirable because ofthe good leverage advantage and also because of the smooth movementcharacteristic. However, it is often necessary to first move this saddlea considerable distance on the jack before it contacts the load. Thispreliminary positioning of the lifting member to a point where it cancommence the lifting operation is time-consuming aswell as beingobjectionable from a standpoint of requiring considerable effort on thepart of the operator.

The present invention provides a mechanical lifting jack having aseparate saddle carrying assembly which is quickly adjustable relativeto the rest of the jack so as to quickly position the saddle closelyadjacent the load to be moved. Upon reaching this position, the saddleis then moved by a screw adjustment to move the load.

More specifically, the present invention provides a jack of the abovetype in which the saddle-carrying assembly is telescopingly engaged withthe jack base assembly so as to provide a compact and neat-appearingjack and one which is particularly strong, rigid and efiicient inperforming its intended functions.

The arrangement of the-improved jack is such that the means foreffecting the fast initial movement of the loadengaging member is solocated as to be accessible regardless of the position of the load andis operable without the necessity for any tools and without danger ofthe operator hurting his hands.

Generally, the invention provides an improved mechanical lifting jack ofthe screw type in which means are provided for rapidly moving theload-carrying member through an initial distance of travel to a positionadjacent the load to be moved.

These and other objects and advantages will appear hereinafter as thisdisclosure progresses, reference being bad to the accompanying drawings,in which:

FIGURE 1 is a side elevational view of a mechanical jack whichincorporates the present invention, certain parts being in section orbroken away for clarity;

FIGURE 2 is a perspective view of the jack shown in FIGURE 1;

FIGURE 3 is a sectional view taken on line 3-3 of FIGURE 1, but on anenlarged scale;

FIGURE 4 is an enlarged sectional view taken on line 4-4 of FIGURE 3;

FIGURE 5 is a fragmentary enlarged view, partially in section, of theupper end of the telescoping member of the saddle-carrying assembly;

FIGURE 6 is atop view of the showing of FIGURE 5;

FIGURE 7 is an enlarged fragmentary cross-sectional view of the upperend of the jack showing the manner in which the screw is supported onthe upper end of the main strut; and

FIGURE 8 is an enlarged, fragmentary sectional view of the saddle nutand washer.

Referring in greater detail to the drawings, the jack chosen forpurposes of illustrating the invention is of the bipod type whichincludes a main leg or strut 10 and a secondary leg 11 pivoted theretoby a pin 12. A wire hairpin type leg clamp 13 is pivotally connected atits and partially ICC open end to the lower end of strut 10.and itsclosed end 14 embraces leg 11 to hold the legs apart and in a supportingposition. The lower ends of the legs 10, 11 have base plates 15, 16,respectively, which are fabricated from sheet steel and are weldedthereto. These plates form relatively wide supporting feet for the jackwhich enhance its stability.

The main strut 10 is of channel shape and has a slot 17 extending alongits length on the front side and also has a series of spaced apertures18 along its rear side. This strut is fabricated, for example, from adraw quality strip steel of about number 9 gage, and forms one of thetelescopic members of the jack.

Slidably mounted within the main strut and quickly adjustable relativethereto in any one of a series of positions, is the load-supportingassembly 20. This assembly includes a channel 21 which is generallysquare in crosssection and is slidably mounted in the main strut 10 andthus forms the other telescopic member of the jack.

' Means are provided between these two telescoping channels 10 and 21for securely holding them in any selected position relative to oneanother. This means takes the form of a lock pin 22 which isshiftablymounted in the lower end of channel'Zl and is engageable in anyone of the apertures 18. The lock pin includes a relatively large hookportion 23 which extends through slot 17 and by which the operator cangrasp the-pin by his fingers to pull it against the bias of a spring 24and out of engagement with the aperture in which it may be positioned.The lock pin 22 and its encircling spring 24 are mounted in a sleeve 25which is welded as at 26 and 27 to the inside of channel 21. The pin isalso comprised of an enlarged end 28 which is threaded on one end of anextension of the hook 23. It will be noted that the spring 24 seats atone end on an internal shoulder 29 in the sleeve 25 and at the other endagainst pin 28.

To assemble this locking means so as to prevent its accidentaldisassembly, the sleeve is first welded to the interior of channel 21.The hook is then inserted in the sleeve and the spring then slipped intothe sleeve and around the extending hook portion. The pin portion 28 isthen threaded on the threaded hook extension and the end of the latteris then swaged to prevent removal of the pin. The interior of the sleeveis preferably lubricated with a lightweight grease.

The top of the inner channel 21 is formed, as best shown in FIGURES 5and 6, into a generally circular shape so as to snugly receive thecircular cover 30. Prongs 31 are formed on this top end of the channel,which prongs are adapted to extend into the corresponding holes 32 (FIG.7) in the cover 30.

An axial thrust bearing 33 is mounted on the cover 30 and this bearingsupports the load through the collar 34 as follows.

A long threaded shaft 35 forms a rotatable screw and is located withinthe inner telescoping member 21 and its upper end extends through thecover 30, bearing 33 and collar 34. A handle 36 extends through alignedapertures in the collar 34 and screw 35 to thereby lock them together.The handle is held captive in the collar by any suitable means such asthe snap ring 37, and rotation of the handle causes the screw to rotatetherewith. The weight on the screw shaft 35, as will more fully appear,is transmitted by the anti-friction bearing 33 through the inner channel21 to the main strut 10.

A load-engaging member in the form of a saddle 40 is operativelyconnected with the screw 35 so as to' be moved by rotation of thelatter, as follows.

The saddle is fabricated of sheet steel and includes spaced guideportions 41 and 42 which extend around the screw and between which ispositioned a saddle nut 43 threadably engaged on the screw. The upperend of the saddle nut is formed on a generally spherical radius whichmates with a complementary surface of a washer 44. Washer 44 is locatedbetween the nut 43 and portion 41 of the saddle and transmits force, asthe screw is rotated, from the traveling nut to the saddle to cause thelatter to move with the nut.

Assume the load L to be raised is located near the upper portion of thejack base assembly as indicated by the phantom lines and the saddlehappened to be in the lower position indicated by dotted lines. Ratherthan turn handle 36 until the saddle reached the load, the operatorsimply pulls the hook 23 to disengage the lock pin from its aperture andthe saddle is then manually lifted to a position directly under the loadwhere the lock pin is then allowed to engage the nearest availableaperture 18. This initial movement is accomplished very rapidly and itwill be noted that the lock pin is accessible to be grasped by theoperator regardless of the position of the saddle.

The handle is then rotated to cause the saddle to make firm contact withthe load and further screw rotation causes the load to raise with asmooth movement.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

We claim:

1. A mechanical jack comprising, a pair of upwardly extending channels,one telescoping within the other and both having a slot along one oftheir corresponding sides, a threaded shaft rotatably mounted within theinner channel, a load-engaging saddle threadably connected to said shaftand extending through both of said slots, means for rotating said shaftto thereby cause the saddle to move relative to both of said channels,and releasable locking means carried by said inner channel andengageable with the outer channel whereby the inner channel and thesaddle can be quickly moved as a unit relative to the outer channel andlocked in any one of a plurality of positions relative thereto, saidlocking means having an actuating portion extending through the slot ofsaid outer channel.

2. A mechanical lifting jack comprising, a pair of upwardly extendingchannels, one telescoping within the other and both having a slot alongone of their corresponding sides, a threaded shaft rotatably mountedwithin the inner channel, a load-engaging saddle threadably connected tosaid shaft and extending through both of said slots, means for rotatingsaid shaft to thereby cause the saddle to move relative to both of saidchannels, said outer channel having a series of spaced apertures alongits length, and a spring-biased locking pin slidably carried by thelower end of the inner channel and adapted to selectively engage any oneof said apertures in said outer channel whereby the inner channel andthe saddle can be quickly moved as a unit relative to the outer channeland locked in any one of a plurality of positions relative thereto, saidlocking pin having a gripping and manipulating portion extendingoutwardly through the slot of said outer channel and adapted to coactwith said outer channel when pulled outwardly and rotated to therebyretain said pin in disengaged condition during movement of said innerchannel relative to said outer channel.

3. A mechanical lifting jack comprising, a pair of upwardly extendingchannels, one telescoping within the other and both having a slot alongone of their corresponding sides, a threaded shaft rotatably mountedwithin the inner channel, a saddle nut threadably engaged by said shaftfor running therealong when the latter is retated, a load-engagingsaddle extending through both of said slots and having a portion forminga sliding fit with the interior of said inner channel and engaged bysaid nut, means for rotating said shaft to thereby cause the nut to movethe saddle relative to both of said channels, and a releasable lockingpin carried in a tubular housing secured to a lower portion of saidinner channel and having one end resiliently urged toward lockingengagement with said outer channel while the other end of said pinextends through said slots whereby the inner channel and the saddle canbe quickly moved as a unit relative to the outer channel and locked inany one of a plurality of positions relative thereto.

References Cited in the file of this patent UNITED STATES PATENTS918,062 King Apr. 13, 1909 953,157 Spencer Mar. 29, 1910 1,156,789 LoughOct. 12, 1915 2,630,295 Lucker Mar. 3, 1953 2,711,183 Lofstrand June 21,1955 FOREIGN PATENTS 1,032,608 France Apr. 1, 1953 124,910 Great BritainApr. 10, l9l9

